Shares of South Africa’s Kumba Iron Ore tumble more than 7 percent putting the producer of the steel-making ingredient on track for its biggest one-day loss in five months, after weak Chinese trade data added to fears of a slowdown in Kumba’s biggest market.

Data on Saturday showed China’s exports unexpectedly tumbled, swinging the trade balance into a deficit and increasing concerns the world’s second-largest economy was cooling. China accounted for 62 percent of Kumba’s 2012 revenue, meaning the company could be hit hard by slowing growth there.

Shares of Kumba were down 7.2 percent at 395.20 rand at 0821 GMT, on track for their biggest one-day loss since October.